Network node and a system
View Patent ↗The invention is related to structures used for providing fault tolerance in computer data networks. According to the invention, fault tolerance is achieved by redundancy, i.e. by using at least two network nodes in parallel. The network nodes have at least two physical network interface to a network, only one of which is active during normal operation. In the case of two network nodes being used, both of these have two physical network interfaces to the same network. A first network interfaces on the first node has the same IP and MAC address as one interface on the second node, and the second network interface on the first node has the same IP and MAC address as the other interface on the second node. The IP and MAC addresses of the two interfaces of each node are different, whereby the two nodes provide a first IP address and a corresponding first MAC address, and a second IP address and a corresponding second MAC address. In normal operation, a first node of the two nodes handles traffic directed to the first IP address and ignores the traffic directed to the second IP address, and the second node handles traffic directed to the second IP address and ignores the traffic directed to the first IP address. The two nodes monitor each other for fault conditions, and if one of the nodes show signs of failure, the other node activates the other of its interfaces and starts handling traffic directed to both IP addresses.
1. A network node for use in a network node group for connecting a first IP network segment to a second IP segment, comprising:
a first physical interface for connection to said first IP network segment;
a second physical interface for connection to said first IP network segment;
third physical interface for connection to said second IP network segment; and
a fourth physical interface for connection to said second IP network segment;
a first operating state, in which said network node communicates using said first and third physical interfaces and ignores any communication received using said second and fourth physical interface, and
a second operating state, in which said network node communicates using said first, second, third and fourth physical interfaces,
a monitoring connection to another network node;
diagnostics unit monitoring the internal operation of said other network node over said monitoring connection and producing an indication about the operational state of said another network node;
a network being arranged to change its operating state from said first operating state to said second operating state as a response to an indication about the operational state of said another network node corresponding to a fault in the operation of said another network node.
2. A network node according to claim 1 , wherein the node is a firewall node.
3. A network element according to claim 1 , wherein said diagnostics unit performs diagnostics test in the network element and reports results of said tests to said other node over said monitoring connection.
4. A network element according to claim 1 , wherein said monitoring of operation of said other network node includes receiving results of diagnostics test over said monitoring connection from said other network element.
5. A network element according to claim 4 , wherein said diagnostic test performed by said diagnostics unit comprises at least one of testing a functioning of disc drivers, testing functioning of network interface cards of said interfaces, monitoring amount of free disc space, and monitoring amount of free memory space.
6. A system for connecting a first network segment to a second network segment comprising:
a first network node having:
a first physical interface for connection to said first IP network segment;
a second physical interface for connection to said first IP network segment;
a third physical interface for connection to said second IP network segment, and
a fourth physical interface for connection to said second IP network segment;
a second network node having:
a fifth physical interface for connection to said first IP network segment;
a sixth interface for connection to said first IP network segment;
a seventh physical interface for connection to said second IP network segment, and
an eigth physical interface for connection to said second IP network segment;
each of said interfaces having an IP address;
said fifth physical interface having the same IP address as said first physical interface;
said sixth physical interface having the same IP address as said second physical interface;
said seventh physical interface having the same IP address as said third physical interface;
said eighth physical interface having the same IP address as said fourth physical interface;
a first operating state, in which said first network node communicates using said first and third physical interfaces and ignore any communication received using said second and fourth physical interface, and in which the second network node communicates using said sixth and eighth physical interfaces and ignores any communication received using said fifth and seventh physical interface;
a second operating state, in which said first network node communicates using said first, second, third, and fourth physical interfaces;
a third operating state, in which said second network node communicates using said fifth, sixth, seventh and eighth physical interfaces;
a monitoring connection between said first and second network nodes;
a first diagnostics unit in said first network node observing the internal operation of said second network node over said monitoring connection and producing an indication about the operational state of said second network node;
a second diagnostics unit in said second network node observing the internal operation of said first network node over said monitoring connection and producing an indication about the operational state of said first network node;
said first network node being configured to change its operating state from said first operating state to said second operating state as a response to an indication about the operational state of said second network node corresponding to a foault in the operation of said second network node, and
said second network node being configured to change its operating state from said first operating state to said third operating state as a response to an indication about the operational state of said first network node corresponding to a fault in the operation of said first network node.
7. A system according to claim 6 , wherein the system is a firewall system.
8. A network element according to claim 6 , wherein first diagnostics unit observes the operation of said second network element by means of diagnostic tests performed in said second network element.
9. A network element according to claim 8 , wherein said second diagnostics unit performs diagnostic tests in said second network element and reports results of said diagnostics tests to said first diagnostics unit in said first network node over said monitoring connection.
10. A network element according to claimed 6 , wherein said second diagnostics unit observers the operation of said first network element by means of diagnostics tests performed in said first network element.
11. A network element according to claim 10 , wherein said first diagnostics unit performs diagnostics tests in the first network element and reports results of said diagnostics tests to said second diagnostics unit in said second network node over said monitoring connection.
12. A network element according to any one of claims 3 to 11 , wherein said diagnostic tests performed by said diagnostics unit compriese at least one of testing a functioning of disc drives, testing functioning of network interface cards of the interface.